As is well-known in the art, normal hair growth occurs by a cycle of activity which involves alternating periods of growth and rest. This cycle is often divided into three main stages which are known as anagen, catagen, and telogen. Anagen is the growth phase of the cycle and may be characterized by penetration of the hair follicle deep into the dermis with rapid proliferation of cells which are differentiating to form hair. The next phase is catagen, which is a transitional stage marked by the cessation of cell division, and during which the hair follicle regresses through the dermis and hair growth is ceased. The next phase, telogen, is often characterized as the resting stage during which the regressed follicle contains a germ with tightly packed dermal papilla cells. At telogen, the initiation of a new anagen phase is caused by rapid cell proliferation in the germ, expansion of the dermal papilla, and elaboration of basement membrane components. This cycle is repeated throughout hair growth. Wherein hair growth ceases, most of the hair follicles reside in telogen and anagen is not engaged, thus causing the onset of full or partial baldness.
A main function of mammalian hair growth is to provide environmental protection. However, that function has been lost in humans, in whom, hair is kept or removed from various parts of the body, essentially for cosmetic reasons. For example, for women in the United States, it is generally preferred to have hair on the scalp, but not on the legs, underarms, or certain areas of the face.
Various procedures and personal care products have been developed to remove unwanted hair, including shaving, electrolysis, depilatory creams or lotions, depilatory devices, waxing, plucking, therapeutic androgens, and laser hair removal. However, such conventional procedures frequently have drawbacks associated with them. Shaving, for instance, may cause nicks, cuts, rash and irritation and often leaves an undesirable stubble. Electrolysis and laser hair removal can keep a treated area free of hair for prolonged periods of time, but can be either expensive, painful, and/or sometimes leave scarring. Waxing and plucking are painful and are poor options for shorter hair. Anti-androgens, used to treat female hirsutism, can have unpleasant physical side effects as well as possible birth defect implications. Since in non-hirsutistic females, the role of androgens is not required for normal hair growth, there is a need for technologies that do not function via androgen mediated pathways due to the birth defect implications. Depilatory devices can be painful to use and are not well-suited for many areas of the body including underarms and face. Finally, depilatory creams, although effective, are messy to apply and typically are not recommended for frequent use due to their high irritancy potential.
Therefore, a need exists for a safe, effective way to not only regulate the condition of mammalian keratinous tissue, but also to retard, inhibit, and/or stop unwanted mammalian hair growth on designated areas of the body.
Surprisingly, it has now been discovered that compositions containing agmatine and its sulfate salt, in combination with other selected skin care actives, are useful for regulating mammalian hair growth, including retarding, inhibiting, or eliminating hair growth. Without being limited by theory, it is believed that agmatine is able to modulate hair growth by inhibiting protease activity in and surrounding the hair follicular unit in mammalian skin. Proteases are key components in restructuring of the extracellular matrix during follicular progression through the dermis of skin in early anagen. Additionally, proteases play a role in angiogenesis, a key process for vascularization of the hair follicle during early anagen as well as maintenance of the vasculature bed during all of anagen. Additionally, it is believed that agmatine can modulate hair growth by upregulating antizyme, a protein that regulates and degrades ornithine decarboxylase (ODC). Omithine decarboxylase is a critical enzyme for cell viability. Agmatine can therefore inhibit ODC activity indirectly by upregulating antizyme. Thus, agmatine plays a role in blocking structural remodeling of the hair follicular unit as well as inhibiting the vascularization of the follicular unit and hair follicle cellular proliferation via ODC, thereby altering mammalian hair growth properties.
Surprisingly, it has also been discovered that select skin care compositions such as BHT or BHA, cetyl pyridinium chloride, hexamidine, and ursolic acid can be used alone for regulating mammalian hair growth, including retarding, inhibiting, or eliminating hair growth.
None of the existing art provides all the advantages and benefits of the present invention.